急性心房压力增高对心房肌电生理性质的影响

目的:探讨急性心房压力增高对心房肌电生理性质的影响及其与房性心律失常的关系。方法:12只杂种成年犬,在阻断自主神经状态下行心外膜电生理检查,分成基础对照组,单纯升压组及胺碘酮 升压组,分别测量心房不同位点的单相动作电位(MAP)及房颤诱发率。结果:与基础对照相比,单纯升压组MAPD90明显延长,MAPD90离散度(△MAPD90)增大,RT离散度(△RT)增大,房颤诱发率增加。胺碘酮 升压组MAPD90延长,但△MAPD90减小,△RT在慢频率起搏时减小,但起搏频率增快时逐渐增大,房颤诱发率虽高于对基础对照,但与单纯升压组相比无统计学差异。结论:1)急性心房压力增高后△RT增大,这可能是此时房颤诱发率增高的电生理基础;2)胺碘酮静脉制剂在房压增高时不能有效降低房颤诱发率,推测与这时△RT在快频率起搏时增大有关。

Effects of Acute Increase in Atrial Pressure on Atrial Electrophysiological Properties

Objective:To evaluate the effects of acute increase in atrial pressure on atrial electrophysiological properties and the relationship with atrial arrhythmia.Methods:In 12 mongrel adult dogs,following autonomic blockade,electrophysiology tests were performed.The monophasic action potential(MAP),and the rate of atrial fibrillation induction were measured respectively in baseline group,pressure elevation group and amiodarone pressure elevation group.Results:Compared to baseline,the MAP duration(MAPD90)of pressure elevation group prolonged significantly and dispersion of MAPD90(MAPD90)increased;the dispersion of RT(RT)increased;the rate of atrial fibrillation induction increased.In amiodarone pressure elevation group,MAPD90 prolonged,while MAPD90 decreased;RT decreased during slow pacing,but increased during rapid pacing.The rate of atrial fibrillation induction was higher than baseline while had no significant difference compared with pressure elevation group.Conclusion:1)RT increased when atrial pressure increased acutely,and maybe this is the eleclrophysiological substrate for increased susceptibility to atrial fibrillation induction.2)Intervenous amiodarone could not effectively decrease the rate of atrial fibrillation induction when AP increased,probably attributed to the increased RT during rapid pacing.